In a wireless communications network, multiple cells or base stations (also referred to as “eNBs”) use frequency bands and standardized codebooks for preceding transmission to their respective user equipments (UEs), using multiple transmit antennas. A typical problem of this procedure occurs where several cells or base stations are serving their intended UEs while interfering with each other's signal. This scenario is called “inter-cell interference.” Inter-cell interference constrains the throughput of the wireless network.
FIG. 1B illustrates an exemplary wireless network 100. In such example, base station (BS) 102 is the serving base station for subscriber station (SS) 116, e.g., communications to and from SS 116 are conducted through BS 102. BS 103 is the serving base station for SS 115, e.g., communications to and from SS 115 are conducted through BS 103. SS 116 is located in proximity to SS 115. Further, BS 102 is communicating with SS 116 using the same frequency band that BS 103 is using to communicate with SS 115. Therefore, SS 116 receives communications 140 from BS 102. However, SS 116 also receives communications 145 (e.g., interfering communications) from BS 103. Further, SS 115 receives communications 150 from BS 103. Additionally, SS 115 also receives communications (e.g., interfering communications not shown) from BS 102. Since SS 116 and SS 115 are in close proximity and using the same frequency band simultaneously, the communications between the subscriber stations, SS 116 and SS 115, and their respective base stations, BS 102 and BS 103, interfere with each other.
For example, SS 116 will report to BS 102 that SS 116 is experiencing high interference. BS 102 will then send an indication message to BS 103 requesting BS 103 to reduce the transmission power over particular resource blocks. In this sense, the interference from BS 103 to SS 116 can be reduced. However, for the case of where SS 115 is also a cell-edge user, reducing transmission power at BS 103 will result in poor performance at SS 115. Inter-cell interference coordination mainly focuses on assigning orthogonal spectrum resource to cell-edge UE's from adjacent cells to combat interference.